In the recent years, researchers have paid a lots of attention in the field of active matter [1]}, [2]}, [3]}, [4]}, [5]}, [6]} because of their unusual properties in comparison to their equilibrium counterparts. Examples of active systems ranges from microscale such as bacterial colonies, cell suspension, artificially designed microparticles [7]}, [8]}, [9]}, [10]}, [11]}, [12]}, etc. to the larger scale; fish school, flock of birds [13]}, [14]}, [15]} etc.
Active system continuousely evolve with time which leads to nonequilibrium class with intresting features i.e; pattern formation [16]}, nonequilibirum phase transition [17]}, [18]}, [19]}, [20]},
large density flcutuations [21]}, enhanced dynamics
[22]}, [23]}, [8]}, motility induced phase separation [25]}, [26]}, [27]}, [28]} etc.
In recent years, the motion of passive particles
in the presence of an active medium
is used to explore the nonequilibrium properties of the medium.
In such mixtures passive particles exhibit enhanced diffusivities \(D_{eff}\)  greater than their thermal (Brownian) diffusivity \(D_0\)  [29]}, [30]}.
In the experiment of [31]}, passive Brownian disks in active bacterial solution show enhanced diffusivity.
The enhanced diffusivity \(D_{eff}\)  increases linearly with increasing concentration of bacteria in the solution [32]}, [33]}, [34]}.
A variety of studies have focused on the role of bacterial concentration on passive particle diffusion.
The effect of passive particles size is still not clear. In the absence of bacteria, or the equilibrium fluid the diffusivity of a sphere follows the Stokes-Einstein relation [35]}.
To understand the role of particle size on their dynamics in the active medium,
we introduce a binary mixture
of active run and tumble \(ARNPs\)  and passive particles.
\(ARNPs\)  move in a straight line for some time and then undergo a random rotation (tumble event).
Hence activity can also be tuned with tumbling rate. A large tumbling rate means smaller run time and hence more random motion.
